Functional analysis of neutrophils has been investigated using bioimaging techniques. Because neutrophils work with dynamic action as follows. Neutrophils circulate in blood to survey and recognize invasion from outside and play real innate immunity and host defense. When the neutrophils recognize an invader and/or the substances produced from it, the neutrophils are stimulated, adhere to the endothelium of the blood vessels, produce a chemotaxis response to the invader, and ingest the invader finally. In particular, the morphological changes and the production of such a large number of reactive molecules within a few minutes are observed following initial stimulation. Therefore, the rapid changes in the morphology and signal cascades have been investigated using cell biology, biochemical and molecular techniques, and imaging techniques that have recently been developed. This review describes the recent works on imaging of chemotaxis and transmigration.
Adrenal capsule, the connective tissue enclosing the adrenal gland, is composed of several layers of flattened cells. Cells of the inner layer of this capsule have been reported to resemble smooth muscle cells and are named myofibroblasts. To better understand the nature of myofibroblasts, we examined rat adrenal capsule by electron and confocal microscopy. In thin-section electron microscopy, myofibroblasts were seen to form an inner zone of 3-5 cell layers, which were clearly identified by the abundance of microfilament bundles and the occurrence of basement membrane covering the entire cell surface. Confocal microscopy of whole-mount preparations of adrenal glands stained with fluorescence-conjugated phalloidin revealed the overall distribution of actin bundles in the capsule. Myofibroblasts contained conspicuous actin bundles running in various directions parallel to the cell layer. Myofibroblasts also showed positive immunoreactivities for smooth muscle α-actin and myosin together with positive staining with vimentin, desmin, and vinculin antibodies. These findings demonstrate that myofibroblasts in the adrenal capsule express a phenotype similar to vascular smooth muscle cells, indicating the possibility that myofibroblasts may have an influence upon secretory activity in adrenal glands.